This invention relates to a single-use syringe of a type which comprises a tubular body wherein a plunger is slidable in sealed relationship, a needle mounted in said tubular body at a first axial end thereof and being movable between a first, safe position and a second, working position whereat said needle is retracted into and extended from said body, respectively, through an opening in the latter, a spring biasing said needle toward its retracted position, said needle being temporarily lockable in its working position.
Re-use of a syringe by many is one of the factors that promotes the spreading of diseases whose infection is passed on by contact with infected blood.
Typical is the spreading of AIDS among people addicted to injectable drugs, where there is a habit of sharing one syringe with several persons.
The most popular of know syringes, while explicitly intended for single use, may nevertheless be used more than once without impairing their mechanical efficiency.
Further, and besides the risk represented by possible re-use thereof, such syringes involve a serious risk of incidental pricking because the needle is left exposed on the tubular body after use of the syringe with no safeguard of sort.
In an effort to obviate such drawbacks, syringes have been developed which incorporate provisions to prevent their re-use and/or a retractable needle, to thereby eliminate the risks connected with the handling of a used syringe.
Typical examples of such improved syringes are described in U.S. Pat. Nos. 4,675,005; 4,747,829; 4,692,156; PCT Application No. W088/06461; European Patent Application No. 282097; and U.S. Pat. No. 4,747,830.
However, it has been found that the engineering of these prior types of syringes has resulted in relatively elaborate constructions, quite unsuited to syringes which may be small in size as are use, in particular, by drug addicts. In addition, some of these syringes can be returned to a working condition after use by relatively simple operations to permit their re-use.
The problem underlying this invention is to provide a single-use syringe which is structured and operated in such a manner as to first eliminate any problems in handling a used syringe, and secondly, make re-use of the syringe practically impossible.